We hope to broaden our understanding of the carcinoplacental antigen, the Regan isoenzyme, as it relates to anomalous gene expression in human cancer. This phenomenon is part of the picture which includes "fetal antigens" and ectopic polypeptide hormone production by human cancer. We plan to extend our work on Regan isoenzyme, to begin work on tumor non-Regan isoenzymes and to examine representative phosphohydrolases, such as acid phosphatase, as potential carcinoplacental antigens. It now appears that we have successfully cloned out two HeLa cell lines, one of which produces only Regan isoenzyme and the other, only non-Regan isoenzyme. Once these cell lines have been properly characterized and evaluated, we will be in a position to investigate known inducers, such as hydrocortisone and prednisone, inhibitors of DNA synthesis (hydroxyurea), and of DNA- directed RNA synthesis (Actinomycin D). Translational inhibitors such as puromycin, cycloheximide, chloramphenicol and BUdR will be included. Prior to this, the kinetics of the cell cycles of these two cell lines would be completed as a basis for all the inhibitor studies. For the better separation and study of Regan and non-Regan isoenzymes, we are developing a new method for separating isoenzymes based on the use of amino acid inhibitor Sepharose 4B column chromatography. Coupled with this are attempts to modify existing isoelectric focusing methodology. Finally, ultrastructural studies are aimed at specifically localizing isoenzymes of phosphohydrolases in HeLa cells and tumor issue to provide a better basis for interpretation. BIBLIOGRAPHIC REFERENCES: Chang, C.H., Raam, S., Angellis, D., Doellgast, G.J., and Fishman, W.H. A simple radioimmunoassay of human placental alkaline phosphatase (Regan isoenzyme) employing specific antibody polymers. Cancer Research 35: 1706-1712, 1975. Fishman, W.H. and Singer, R.M. Placental alkaline phosphatase: regulation of expression in cancer cells. Annals N. Y. Acad. Science 259: 261-272, 1975.